.gitlab-ci.yml

 workflow:
-  rules:
-    - if: >-
-        $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_BRANCH == "main"
-      when: 'always'
-    - when: 'never'
+#  rules:
+#    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
+#      when: 'always'
+#    - if: $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_REF_NAME =~/main/
+#    - when: 'never'
 
+stages:
+  - test
+  - build
+  - publish
 
-job_trigger-pipeline:
-  trigger:
-    project: 'fb6-wp11-devops/webservice-build-and-publish'
+# Main job to test the application
+job_test_the_code:
+  stage: test
+  image: registry.hub.docker.com/library/golang:1.21 # Official Docker image provided by Go. It contains pre-configured environment for building and running Go applications.
+  script:
+    - go get -t ./... # Installs dependencies, including those for testing
+    - go test -race -v ./... # Run tests with race detection enabled
+
+job_build_artifact:
+  stage: build
+#  rules: # Conditions under which this job should run
+#    - if: $CI_PIPELINE_SOURCE == "merge_request_event" && $CI_MERGE_REQUEST_TARGET_BRANCH_NAME == "main"  # Run this job only for merge request event into main.
+#      when: always
+  image: registry.hub.docker.com/library/golang:1.21
+  script:
+    - go get -t ./... # Installs dependencies
+    - go build -o ./artifact.bin ./*.go # Builds the Go application and outputs a binary named artifact.bin
+  artifacts:
+    paths: # Specifies the paths to the files that are to be saved as artifacts after the job has been completed.
+      - ./artifact.bin
+    expire_in: 1 week
+
+job_build_and_publish_image:
+  stage: publish
+#  rules: # Conditions under which this job should run
+#    - if:  $CI_PIPELINE_SOURCE == "push" && $CI_MERGE_COMMIT_REF_NAME =~ /main/  # Run this job only for merge request event into main.
+#      when: always
+  image: docker:24.0.0 # Official Docker image with Docker client installed
+  services:
+      - docker:24.0.0-dind # used to access the Docker daemon from within the CI job.
+  tags:
+    - docker-privileged
+  dependencies:
+    - job_build_artifact
+  before_script:
+    - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" "$CI_REGISTRY"
+  script:
+    - echo "Publishing artifact ..."
+    - ls -al
+    - docker build -t "$CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG" .
+    - docker push "$CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG"
+  after_script:
+    - docker rmi "$CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG"
\ No newline at end of file

Dockerfile

+## 1. Basisimage auswählen
+FROM golang:1.21
+
+# Set the working directory inside the container
+WORKDIR /app
+
+# Copy go.mod and go.sum files first to cache dependencies
+COPY go.mod go.sum ./
+
+# Copy the rest of the application code
+COPY . .
+
+RUN go build -o artifact.bin ./*.go
+
+# Set environment variables
+ENV HOST=0.0.0.0
+
+# Expose the port the application runs on
+EXPOSE 8080
+
+CMD ["./artifact.bin"]
+
+RUN echo 'hello world'
+
+